Refill fuse plug



March 4, 1941. J, CREE ETAL 2,234,024

REFILL FUSE PLUG Filed Ag. 1o, 1939 ZOMV 55.1. |:1f-E- 36 35 1"113635FMI-r. El. 29

|4- InUEnLuI'S J. CREE: Il. H WRME Patented Mar. 4, 1941 PATENT OFFICEREFILL FUSE PLUG John Cree and David Anthony Worme, Hamilton Ontario,Canada Application August 10, 1939, Serial No. 289,442

7 Claims.

Our invention relates to improvements in rell fuse plugs and an objectof the invention is to devise a plug adapted to contain a plurality ofseparate fuse elements wherein any selected fuse element of theplurality may be thrown into circuit without removing the plug from thesocket or holder when one of the fuse elements which has previously beenin circuit is fused by an overload.

A further object is to devise a rell fuse plug in which the plurality offuse elements may be inserted and removed from the plug as a unitinstead of separately.

A still further object is to provide an im- F proved fuse element ofbi-metallic construction particularly adapted for use with our plugwherein the ends are constructedv of a metal insusceptible to fusingunder ordinary overloads, whereas the body is composed of the orthodoxfuse metal capable of fusing upon being subjected to current greaterthan for which it is designed.

With the above and other objects in View w which will hereinafter appearas our specication proceeds, our invention consists, in its preferredconstruction, of the construction and are rangement all as hereinaftermore particularly described and illustrated in the accompanying drawingin which:

Fig. 1 represents a vertical section through a fuse holder or socket ofthe screw shell type showing our refill fuse plug (in elevation) screwedthereinto.

Fig. 2 is a vertical section of our plug taken on the line 2-2 (Fig. 4)

Fig. 3 is a vertical section thereof taken on the line 3-3 (Fig. 4), thecapsule being shown in elevation.

Fig. 4 is a top plan View of our plug.

Fig. 5 is a side view of the insulating body of our plug.

Fig. 6 isV an inverted plan view thereof.

Fig. 'l is a top plan View of the capsule showing the plurality of fuseelements mounted thereon.

Fig. 8 is an inverted plan View thereof partly in section.

Fig. 9 is an elevational detail of a manually operable rotatable contactfor throwing any sen lecterl fuse element into circuit.

Fig. 10 is a detail in plan showing the means for mounting the fuseelements whereby they may be inserted into and removed from the capsuleas a unit, and

Figs. 1l and 12 are respectively plan and edge views of one of ourbi-metallic fuse elements.

Like characters of reference indicate corresponding parts in thedifferent views of the drawing.

Our rell fuse plug comprises an exteriorly threaded cylindricalinsulating body I preferably composed of heat resisting glass with aperipheral flange 2 (by means of which the plug is screwed into andunscrewed from the screw shell 3 of the holder 4) in the vicinity of itsclosed end 5. The other end of the body I is open and provided with aplurality of spaced apart notches 6.

The capsule 1 of insulating material such as porcelain is generallycylindrical in shape and hollow and has a circumferential flange 8therearound intermediately of its length with a plurality of spacedapart` lugs 9 on the upper face of such flange adapted to be insertedinto the notches 6 when the capsule 'I is inserted into the body I withits flange 8 resting on the lip of the open end of the body. Theinterior of the capsule has a central contact receiving bore I0 ofreduced diameter at its lower end and the upper lip of the capsule isprovided with diametrical extending grooves II. The wall of the upperpart I2 of the capsule is` provided with a plurality of vertical spacedapart fuse element receiving grooves I3 with their inner surfacesconcave in longitudinal section, said grooves being located on thecapsule between the lugs 9 on its flange 8.

The plurality of fuse elements each comprises a strip of fuse metal I4forming the body of the fuse element ond end strips I5 of normallynon-fusible metal such as copper, sweated or otherwise securedto thestrip I4. The upper end strips I5 are hooked around the periphery of aninsulating disc I B and through spaced apart slots Il in the Vicinity ofits periphery located in radial grooves I8 in the top of the disc, thelower end strips I5 being hooked about the flange 8 of the capsule 'Ialso in spaced relation so that the fuse element portions Ill lie in thevertical grooves I3 in the capsule wall leaving air spaces between theportions I4 and the inner surfaces of such grooves.

The insulating disc I having a central orifice I9 therethrough isdetachably mounted on the upper end of the capsule 'I with pimples 2t)inserted into the diametrical grooves il for preventing it rotatingrelatively to the capsule, and is held on such capsule by the lower endsI5 of fuse elements being hooked over the flange 8 as above referred to.

A metallic screw shell 2| having an inturned flange 22 at its outer enddefining a central circular opening to receive the lower part 23 of thecapsule is threaded onto the body I until its flange 22 abuts the flange8 of the capsule and makes electrical contact with the lower ends I5 ofthe fuse elements. An upwardly extending resilient lug 24 formed on theupper end of the screw shell 2I is adapted to be inserted into anindentation 25 in the body I for positively locking the screw shell 2|to the body against relative rotation when the plug is screwed into theholder 4.

When the plug is disconnected from the holder the lug 24 does not lockthe screw shell 2| to the body as the lug is not then located in theindentation 25 having, due to its resiliency, di=- engaged itselftherefrom.

Prior to the application of the screw shell 2l to the body I a spindle26 carrying the central contact 21 at its lower end is inserted into thecapsule with the contact 21 extending through the bore Il) andprotruding therefrom. The contact 21 is provided with an air vent 21d inthe form of a vertical slit in its periphery. The upper end of thespindle extends freely through an orifice 28 in the upper end 5 of thebody I and has a squared extremity 29 protruding exteriorly thereof towhich is cemented or otherwise secured the actuating knob 3D.

A boss 3| is provided on the spindle 2B intermediately of its lengthfrom which extends a radial finger contact 32 adapted to make contactwith the respective upper ends I5 of the fuse elements. A leaf spring 33having a central orifice 34 is provided on the spindle 2E between theboss 3l and the upper end 5 of the body I.

Radial fuse indicating notches 35 are located on the flange 2 of thebody I in register with the grooves I3 in the capsule and therefore withthe fuse elements therein, and similar notches or serrations 36 may beprovided on the knob 30.

When the plug is once screwed into the holder it is unnecessary toremove it until all the fuses are burnt out. The finger contact 32 isinitially set by rotating the spindle by means of the knob 30 so thatsuch nger contacts with the upper end I5 of any one fuse element. Whensuch fuse element due to overload is burnt out, it is only necessary topull out the knob a limited extent against the action of the spring 33and rotate the spindle until the linger contact enters the next radialslot I8 wherein the finger makes Contact with the upper end I5 of thenext fuse element.

The provision of the vent 21a and the radial grooves II as well as theconcave surfaces in the grooves I3 enables the gases resulting from thefusing of the fuse elements to be adequately vented.

When all the fuse elements attached to the disc have been burnt out theplug may be removed and the screw shell 2| unscrewed from the body. Thecapsule may then be removed, leaving the spindle 26 in position, and theunfused portions of the fuse elements may then be detached from thecapsule flange and disc and replaced by a fresh supply of fuse elementswhen the plug may be then reassembled. Alternatively, if desired, therefill instead of consisting of new fuse elements alone may consist of anew disc as well with the new fuse elements already assembled thereon.

What I claim as my invention is:

1. A fuse plug comprising an externally threaded hollow body ofinsulating material open at one end, a hollow fuse element carryingcapsule of insulating material having a peripheral outwardly directedflange extending therearound intermediately of its length, said flangeadapted to seat on the lip of the open end of the body, a plurality ofindependent fuse elements entirely mounted on the side and one end ofthe exterior of the capsule, a metallic screw shell adapted to bescrewed on the threaded body and make electrical contact with thecorresponding end of each fuse element located on the side of theexterior of the capsule, and means in the body including operable meansdisposed exteriorly thereof for selectively making electrical contactwith the other ends of the fuse elements on the end of the capsule.

2. The invention claimed in claim 1 wherein a member of insulatingmaterial is superimposed On the inner end of the capsule and the ends ofthe fuse elements adapted to make contact with the contact means in thebody are attached to such member, and such contact means in the body isrotatable axially therein and includes an outwardly extending contactadapted to make electrical contact selectively with the respective endsof the fuse elements attached to the member of insulating material.

3. The invention claimed in claim l wherein a disc of insulatingmaterial having a plurality of radial grooves in a face thereof withslots in such grooves in the vicinity of its periphery is mounted on thecapsule, and the ends of the fuse elements adapted to make contact withthe contact means in the body are hooked through the slots and extendinto the grooves, said contact means in the body being axially rotatabletherein, and an outwardly extending contact on the ccntact means in thebody adapted to make electrical contact selectively with the respectiveends of the fuse elements extending into the grooves in the disc.

4. The invention claimed in claim 1 wherein a disc of insulatingmaterial having a plurality of radial grooves in a face thereof withslots in such grooves in the vicinity of its periphery is mounted on thecapsule, and the ends of the fuse elements adapted to make contact withthe contact means in the body are hooked through the slots and extendinto the grooves, said contact means comprising a longitudinally movableand rotatable metallic spindle extending axially and freely through thebody, disc and capsule and including a Contact protruding from the outerend ofthe capsule and an outwardly extending contact locatedintermediately of the length of the spindle for selectively makingelectrical contact with the respective ends of the fuse elementsextending into the grooves in the disc.

5. The invention claimed in claim 1 wherein a disc of insulatingmaterial having a plurality of radial grooves in a face thereof withslots in such grooves in the vicinity of its periphery is mounted on thecapsule, and the ends of the fuse elements adapted to make contact withthe Contact means in trie body are hooked through the slots and extendinto the grooves, said contact means comprising a longitudinally movableand rotatable metallic spindle extending axially and freely through thebody, disc and capsule and including a contact protruding from the outerend of the capsule and an outwardly extending contact locatedintermediately of the length of the spindle for selectively makingelectrical contact with the respective ends of the fuse elementsextending into the grooves in the disc, said spindle protrudingexteriorly of the body, and a knob of insulating material on suchprotruding end.

6. The invention claimed in claim 1 wherein a plurality of spaced apartlongitudinal grooves are provided on the exterior of the capsule and thefuse elements are receivable therento, the inner surfaces of suchgrooves being concave in longitudinal section to space the fuse elementsdism posed therein from such inner surfaces.

7. In a fuse plug, a removable capsule of insulatng material having aperipheral flange eX- tending therearound intermedately of its height, amember of insulating material superimposed on the capsule, and apluralit7 of independent fuse elements attached in spaced relation attheir upper ends to the member and extending down the exterior of thecapsule, and hook-shaped lower ends on the fuse elements adapted to behooked over the peripheral edge of the ange.

JOHN CREE.

DAVD ANTHONY WORME.

